A novel Ultra Wideband (UWB) antenna on double substrates crossing is presented in this paper. Based on conical antenna and microstrip patch UWB antenna, the proposed antenna is omnidirectional, band-notched and easy to be fabricated. It operates from 2.6 GHz to 12 GHz with low Voltage Standing Wave Ratio (VSWR < 2), excluding a notch-band of 5.8 GHz. Except for good performance of VSWR, the proposed antenna keeps its radiating beam at about θ = 45 • in E-plane through the whole band. The UWB antenna is fed by a coaxial probe through a SMA connector. The length of the proposed monopole element above the ground is slightly less than λ/4 of the lowest frequency. The simulated and measured results of the VSWR, the gain and the radiation patterns for the proposed antennas are presented and discussed. Good agreement between simulated and measured results is demonstrated.

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A novel omni-directional Ultra-Wide Band (UWB) biconical antenna with band-notched is described. Firstly, the biconical antenna in the shape of two kinds of bicone placed above a flat ground plane is designed. The antenna operates from 2.4-20 GHz with low Voltage Standing Wave Ratio (VSWR<2), excluding a band-notched frequency at 5-7GHz. Then in order to improve the structure of the ground plane for miniaturization without degrading the VSWR, ground plane shaping is introduced leading to an antenna that operates from 2.4-20 GHz with low VSWR (<2) too. The biconical antenna is fed by a coaxial probe through a SMA connector. The length of the proposed biconical element above the ground plane is slightly less than O /4 at the lowest frequency in the band. Simulation results for VSWR and radiation pattern of the three antennas are presented and discussed.

Abstract-The cosine window function with the parameters optimized by Genetic Algorithm (GA) is applied in bistatic planar nearfield scattering measurements so as to effectively improve the measurement precision. With the infinitely long ideal conductor cylinder as the target under test, the bistatic planar near-field scattering measurement technique is studied by the method of computer simulation and some useful results and basic laws are obtained. The calculation results show that the truncation errors caused by finite scan plane in the far-field Radar Cross Section (RCS) of the target under test obtained by near-field to far-field transformation can be reduced greatly by the weighting process of the measured scattered near-field data by means of the cosine window function with the parameters optimized by GA.

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